With Mitt Romney having all but sewn up the Republican presidential nomination, there is only one task left for restless political junkies and reporters for the next four months: predict Romney's running mate.

I constantly make the argument that the significance of the vice-presidential nomination is often overblown, assuming greater importance than it deserves. To paraphrase James Carville, it's the presidential candidate, stupid, not the number two, who really makes the difference. Go back no further than 1988, when George H.W. Bush picked the widely-panned Dan Quayle as his running mate, a choice so disastrous that ... the Bush-Quayle ticket won 40 out of 50 states that year.

And four years earlier, there was the Geraldine Ferraro selection, a choice that excited women everywhere, a choice that was going to go down in history. It was, of course historic — Ferraro was the first woman to appear on a major-party ticket. It was historic in another way too: it was an electoral disaster, in which the Mondale-Ferraro ticket lost 49 out of 50 states. It didn't even carry the female vote that year.

Do we blame Ferraro? Do we credit Quayle? It's not that simple. They playsome role, but not a defining one. Still, the choices do matter: it says something about the judgment about the presidential candidate.

To be sure, selecting a running mate has come a long way since 1964, when Barry Goldwater chose Rep. William Miller of New York simply, as Goldwater said, because he "drove LBJ nuts." But that's not to say the process has become less flawed. You didn't have to see the HBO movie "Game Change" to know that John McCain threw a Hail Mary pass in coming up with Sarah Palin. But no Republican would have helped McCain in a year the financial system as we knew it was approaching total collapse and the outgoing GOP president's popularity was at rock bottom.

Walter Mondale's choice of Ferraro was similarly considered a sign of desperation, as nobody was going to defeat President Reagan that year. But the process for the Democrats, in which Mondale seemingly held daily "auditions" for potential running mates, grew unseemly and embarrassing and was criticized by many as little more than a thank you to various special interest groups.

So yes, the election really is about the candidate at the top of the ticket. McCain never excited the GOP "base," and perhaps that was the purpose of his VP choice. But for all of the fanfare of Palin and her convention speech — which was electric — that excitement lasted only a couple of weeks. John Kerry was never a beloved figure in the South, and so picking John Edwards as his running mate to perhaps improve the ticket's chances in the South made some sense. But it was really a doomed strategy from the start. The closest the Democrats came to winning a Southern state that year was Maryland.

Still, most analysts argue that in naming Lyndon Johnson, his chief rival, as his VP in 1960, John Kennedy went on to carry a region of the country that he may not have gotten with a non-Southern running mate — a decision that gave Kennedy a huge electoral college victory that year, even if the popular vote was incredibly close.

So, starting with Kennedy-Johnson as the yardstick, here is my subjective list of the top five instances in the past half century or so where a selection of a running mate was crucial to victory:

1. 1960 (D) — Kennedy-Johnson

Without a doubt, number one. They didn't particularly like each other, having run against each other for the nomination, and we know all about Johnson's relationship with Robert Kennedy. It was an enmity that perhaps lasted all the way until Dallas. It was the first time a presidential ticket was comprised of two senators. And in picking Johnson, JFK followed a familiar path of his party's standard bearer in looking South to a running mate (see: John Nance Garner, Alben Barkley, John Sparkman, Estes Kefauver, etc.). But LBJ was not just as Southerner; he was the most powerful member of the Senate, gave the ticket some conservative credentials, and his addition helped Kennedy in key Southern states. His unhappiness in the job for the next three years is another story.

2. 2000 (R) — Bush-Cheney

The selection of Dick Cheney brought along congressional, Cabinet and foreign policy experience — everything that George W. Bush lacked. He also brought along Washington know-how. It's debatable how much Cheney helped during the campaign (a campaign where Al Gore actually won the popular vote), but once in office Cheney proved to be in an invaluable and influential — if controversial — vice president.

3. 1976 (D) — Carter-Mondale

If George W. Bush had few D.C. credentials, it was even worse for Jimmy Carter. Hardly the choice of the Washington establishment, Carter, a one-term governor of Georgia, actually fed off the public's antagonism towards Washington in this Watergate-inspired election. But he still needed to be able to work with the folks on Capitol Hill, and in picking the widely respected Walter Mondale as his running mate, he got someone who came to the table with ten years' experience in the Senate.

4. 1980 (R) — Reagan-Bush

By selecting George H.W. Bush, his chief rival for the nomination, Ronald Reagan sent a message that the party needed to be united if they were going to defeat President Jimmy Carter. But it was more than that. Almost in response to the charge that he was too out of the mainstream to win, Reagan picked Bush, who as a former congressman, UN Ambassador, RNC chair and CIA director, had solid moderate and establishment credentials.

5. 1992 (D) — Clinton-Gore

All the so-called rules of "ticket balance" were thrown out when Bill Clintonpicked Tennessee Sen. Al Gore to run with him. There was no regional, ideological or demographic balance. Both were young (Clinton 45, Gore 44) and both professed centrist positions on many issues. Coming from neighboring states, they were the Democrats' first all-Southern ticket since 1828. But there was an obvious comfort level between the two, and Clinton's intention to redefine his party succeeded.

Honorable mention:Barack Obama selecting Delaware Sen. Joe Biden in 2008. Obama had been in the Senate for only 15 minutes, and his pick of Biden, in office since 1973, helped balance the experience gap. And Biden fared well in comparison with the clearly over-her-head GOP choice of Sarah Palin for vice president.

All six examples described above were victorious. I'm hard pressed to pick a good running mate selection for a losing ticket in the past half century. Most of them made little or no difference at all. I'd have to go back to 1948, when the Republican presidential nominee, New York Gov. Thomas Dewey, chose California Gov. Earl Warren as his number two. Warren was exceptionally popular at home. And for all the old ticket-balancing reasons, Warren made sense. California was a state of rising importance back in '48, and while it had only 25 electoral votes (compared to 55 now), it trailed only New York, Pennsylvania and Illinois in that category. Still, Warren failed to help the GOP ticket carry the Golden State.

And the most disastrous VP pick? That has to be George McGovern's selection of Sen. Thomas Eagleton of Missouri in 1972. Back in those days, when vetting was hardly an art, nobody knew about Eagleton's electric shock treatment for depression, a fact that came out after the Democratic ticket was announced at the Miami Beach convention. Eagleton was gone in just over two weeks, replaced by Sargent Shriver.

(And speaking of non-existent vetting: go no further than Spiro Agnew, who was taking bribes while Baltimore County Executive, a practice he continued as governor of Maryland. And yet he was Richard Nixon's running mate in 1968.)

Reminder: Today (April 30) is the deadline to submit your "who will be Mitt Romney's running mate" prediction. Guaranteed huge prize for the lucky winner. Or something like that. Send it to politicaljunkie@npr.org.

Pennsylvania results (see last week's column for primary preview). Two more House incumbents went down to defeat in the April 24 primary.

With the state losing one seat because of redistricting, Republican mapmakers put two Democratic congressmen, Jason Altmire and Mark Critz, into the same district, the newly-drawn 12th. Altmire was thought to be the favorite, having already represented nearly two-thirds of those living in the new district. But labor unions were solidly behind Critz, who upset Altmire by a 52-48 percent margin.

In the new 17th, veteran Rep. Tim Holden, like Altmire a Blue Dog Democrat who voted against the Obama health care bill, was trounced by liberal attorney Matt Cartwright. Both seats are likely to remain in Democratic hands in November. Altmire and Holden join three other House members who lost their primary contests for renomination: Dennis Kucinich (D-Ohio), Jean Schmidt (R-Ohio) and Donald Manzullo (R-Ill.).

In the open 4th CD, where GOP incumbent Todd Platts is retiring, the Republican nomination in this solidly Republican district went to state Rep. Scott Perry.

And in the Senate race, businessman Tom Smith won the five-way GOP primary and will face Democratic incumbent Bob Casey.

Gingrich departs. Not every presidential candidate who wins a total of TWO primary states gets a ton of media coverage, but not every presidential candidate is Newt Gingrich. Having attempted a last stand in Tuesday's Delaware's primary — where he finished a weak second to Romney with just 27 percent of the vote — Gingrich is prepared to officially end his candidacy on May 1.

This of course begs the question: had he won Delaware, or even done well, would that have been enough to keep him in the race? And if so, why?

But that's not the point. We are, after all, talking about Gingrich, the always unpredictable and often exhausting former speaker of the House.

Other than perhaps Gary Hart and his short-lived return to the campaign trail in early 1988, it's hard to think of anyone with as much baggage who had serious designs on a presidential nomination.

Where do you start? A personal life that included two divorces and three marriages (one affair taking place as he was leading the Impeach Clinton Because Of Monica crusade), the ethics cases against him while Speaker in the 1990s, being drummed out of the leadership by his own GOP troops, the lobbying for Fannie and Freddie as he was attacking Washington business as usual, the dismissal of Paul Ryan's budget ideas as "right-wing social engineering" ... the list is endless. And yet, nobody captivated the audiences as he did during the early debates, with effective attacks on the moderators and the media leading to sustained ovations. In many ways he would have been a disaster of a nominee for the GOP. And yet there was a time when many pundits, and Gingrich himself, were convinced he was the guy to beat. For me, Newt Gingrich has been fascinating to watch since I first met him in the 1980s, always filled with ideas and energy and willing to talk to anyone who would listen. I never thought his White House ambitions were going to go anywhere, and I certainly never thought he would be part of any "brokered convention" scenario.

If nothing else, he ends one of the shibboleths of politics. Every Republican who has won the South Carolina primary since its creation in 1980 has gone on to win the nomination.

Not this time.

Gingrich will make the end of his campaign official with an announcement on May 1.

Political Updates. I post periodic political updates during the week on Twitter. You can follow me at @kenrudin. Time for two questions from readers:

Q: How many Miss Americas have run for political office or been married to men who have run for political office? — Pete Golkin, Arlington, Va.

A: Let the record show that you sent in this question two years ago. But it is especially relevant today following the announcement that Erika Harold, Miss America 2003, is asking Republican leaders in Illinois' 13th District to consider her as a replacement for Rep. Timothy Johnson (R), who decided to retire after winning renomination in the March 20 primary. Harold, 32, is currently an attorney in Chicago but she grew up in the midst of Johnson's district.

The only Miss America to have ever run for office before was Bess Myerson, who won the crown in 1945. But she didn't win the Democratic nomination for the Senate from New York in 1980, where she came in second to Elizabeth Holtzman. (Holtzman went on to lose to Al D'Amato in a three-way contest.)

As for the second part of your question, I can think of one. Phyllis George of Texas, crowned Miss America 1971, later married John Y. Brown Jr., who was elected governor of Kentucky in 1979. She herself was mentioned as a potential Kentucky gubernatorial candidate in 2007 but never ran.

A: Yes, it's hard to give up the Goode & Pawlenty joke that I've been using to death on TOTN and the podcast these last several years. Goode, the former Democratic-turned Independent-turned Republican congressman who narrowly lost his seat in 2008, is the Constitution Party's presidential nominee this year. Jim Clymer, who has often sought office in Pennsylvania, is his running mate.

Political Junkie segment on Talk of the Nation. Each Wednesday at 2 p.m. ET, the Political Junkie segment appears on Talk of the Nation (NPR's call-in program), hosted by Neal Conan with me adding color commentary, where you can, sometimes, hear interesting conversation, useless trivia questions, and sparkling jokes. Last week focused on the Romney primary sweep, the withdrawal of Gingrich, and profiles of two VP hopefuls, Marco Rubio and Rob Portman. Special guests were Lucy Morgan of the Tampa Bay Times and Mike Thompson of member station WOSU in Columbus, Ohio.

Podcast. There's also a new episode of our weekly podcast, "It's All Politics," up every Thursday. It's hosted by my partner-in-crime, Ron Elving, and me. With Ron off last week, NPR's Mara Liasson pinch hit.

And Don't Forget ScuttleButton. ScuttleButton, America's favorite waste-of-time button puzzle, can be found in this spot every Monday. A randomly-selected winner will be announced every Wednesday during the Political Junkie segment on NPR's Talk of the Nation. You still have time to submit your answer to last week's contest, which you can see here. Not only is there incredible joy in deciphering the answer, but the winner gets a TOTN t-shirt!

Previous winner: Dan Seidman of Watertown, Mass.

Political Junkie cocktail. So we're at the Modern Hotel in Boise, Idaho, for a StateImpact training session. More specifically, we're at the bar. And, surprisingly for me, I'm yakking away. And the bartender says, "You know, your voice sounds like the Political Junkie on NPR." And I say, "My good man, I am the Political Junkie on NPR." And before you know it, Michael, the bartender, makes a drink he calls the Political Junkie cocktail. And trust me, it's pretty good, especially after seven or eight of those things.

Ingredients: one ounce Scotch (he suggests Dewar's White Label), one ounce Irish Whiskey. A half ounce of orgeat. Half ounce of fresh lemon. Add an orange peel. If it sounds sweet, I guess it is. But how could a Political Junkie cocktail not be?

Hotline trivia contest. If you must know, the team comprised of Amy Walters of ABC News, Stephen Hayes of The Weekly Standard, Jonathan Martin of Politico and me finished a close second in the April 26 "political pursuit" contest at the Newseum in Washington. The good news is that we beat out two other teams, including the reigning champions led by former Rep. Tom Davis (R-Va.). But the winners, who have yet to be tested for steroids, were the ragtag team of Greg Giroux of Bloomberg News, Stacey Skotzko of CQ/Roll Call, Jonathan Allen of Politico, and freelancer Mark Greenbaum. See National Journal's writeup of the results here.

June 5 --Wisconsin gov. recall election. Also: primaries in California, Montana, New Jersey, New Mexico and South Dakota.

June 12 — Special election in Arizona's 8th CD to succeed Gabrielle Giffords (D), who resigned. Also: congressional primaries in Nevada, North Dakota, South Carolina and Virginia.

June 26 — Congressional primaries in Colorado, New York, Oklahoma and Utah.

Mailing list. To receive a weekly email alert about the new column and ScuttleButton puzzle, contact me at politicaljunkie@npr.org.

******* Don't Forget: If you are sending in a question to be used in this column, please include your city and state. *********

This day in campaign history: One day after he is sworn in as Chicago's first black mayor, Rep. Harold Washington (D-IL 01) resigns his House seat. Washington was elected April 12 over Republican Bernard Epton in a record mayoral turnout for the city that was dominated by race issues (April 30, 1983). Washington's successor in the House will be Democratic labor leader Charles Hayes, who will win the seat in a special August election.